The proposal would see vehicle fees go from $30 to $70 and motorcycle fees go from $25 to $50 in many of these parks. Plus, even if you avoid driving and you walk or cycle in, you could be charged $30 a head.

Ouch.

The targeted fee increase has been proposed as a solution to the NPS' maintenance backlog of $11.9 billion. According to a fact sheet released by NPS, the increase in revenue, which is estimated at about $68.6 million, will help "improve the visitor experience." That is - if you can even afford the visitor experience.

All in all, it's a bit hard to take these claims seriously when President Trump's budget proposal would cut nearly 13 percent of the NPS budget.

While it is true that some park facilities are badly in need of repair, when the Center for American Progress sat down and looked at the maintenance backlog, they noticed something funny.

It turns out, a lot of taxpayer money is not even being used to maintain the park lands. Instead, the U.S. government routinely bills taxpayers for the maintenance of private hotels, restaurants and concessionaire facilities in national parks. To put it another way, private businesses are being propped up by hundreds of millions of dollars of taxpayer money.

Instead of saving money by making these businesses pay for their own maintenance, the government has shifted the financial burden onto the shoulders of the American people.

Just add this one to the long list of examples where the Trump administration has prioritized businesses over the environment.

But even if the new fees go towards actual park maintenance, many critics worry the expensive charges will price the public out of nature itself. For this very reason, a bipartisan group of attorney generals came out in opposition of the measure on Wednesday.

"The service's proposed fee increases, which double or even triple existing entrance fees, threaten to put many Americans to the choice of beauty or bread and to distance them from the places in which so many experience the natural wonder of our great and unique nation," the attorneys wrote in a public comment.

"This is concerning as a matter of policy."

And it's not just lawyers that are weighing in on the matter. At a recent Sierra Club event, park advocates delivered more than 150,000 comments against the proposal.

"I have spent 15 years working to connect children and families with nature and am all too familiar with the barriers that prevent many communities from feeling welcomed in their public lands," said Jackie Ostfeld, associate director of Sierra Club's Outdoors campaign.

"With this one move, the Trump administration will price many people out of our natural wonders—undermining years of progress in advancing equity and access to our parks. President Trump and Secretary Zinke must abandon this plan."

Already, NPS has received more than 65,000 comments on the proposal. If word continues to spread, chances are that number will be much higher by the end of the comment period, which is now set to December 22.